Paul Manafort

Paul Manafort was charged with crimes unrelated to his brief time (<3 months) as Trump’s campaign chair. Back during the Obama/Clinton administration Manefort was working with Tony Podesta (the brother of Hillary Clinton’s campaign chair John Podesta), and they were lobbying for various foreign interests. He was supposed to register by June 2nd, but didn't do it until June 27th, which allowed the FBI to investigate him and found some financial discrepancies (he didn't bring all foreign money earned back to the States for proper taxation). Tony also appeared to be involved in the exact same shenanigans but since he's a FOH (Friend of Hillary), he's not being railroaded for a political agenda (no charges have been filed against him, nor investigation: that we know of).

2016.06.09 - Manafort, Donald Trump Jr., and Jared Kushner were participants to a meeting with attorney Natalia Veselnitskaya, who claimed she had info on a British Music agent that might have Russian dirt on Hillary. During the meeting Natalia just filibustered on her dislike of the Magnitsky Act. This never went further, no crime committed by anyone, and ethically this was far less grey than Hillary Campaign which had paid for a fake Russian Pee-Pee Dossier months earlier (and is now under campaign violations in paying for it).

2016.06.27 - Manafort registers as a representative of foreign governments (he was supposed to do that on 06.02).

2016.08.17 - Donald Trump received his first security briefing and immediately minimized Manafort's role (presumable he was disclosed on shady things in Manefort's past. Two days later, Trump announced his acceptance of Manafort's encouraged resignation from the campaign.

Yanukovich

After the investigation started into Russian collusion -- against started because of Hillary's fake dossier, and the fake hacking scandal -- they investigated Manefort for being 3 weeks late on declaring he had acted as a foreign agent. That lead them to discover later that he had offshore holdings he hadn't declared. Items of note:

Specific charges are about his 2014 business dealings while he was lobbying for President of Ukraine (not Russia), Viktor Yanukovich.

There's absolutely no ties to Russian collusion: Ukraine is a separate country and generally opposed Russia

There's no ties to the Trump administration, this happened long before he was on the campaign and had nothing to do with the campaign -- and all evidence is that Trump immediately fired Manafort when he found out that he hadn't disclosed everything.

Manafort was a first trimester abortion: being on the campaign for ≈11 weeks.